code: def _make_psd_data():
      """Make noise data with sinusoids in 2 out of 7 channels."""
      rng = np.random.default_rng(0)
      n_chan, n_times, sfreq = 7, 8000, 1000
      data = 0.1 * rng.random((n_chan, n_times))
      times = np.arange(n_times) / sfreq
      sinusoid_freqs = [8.0, 50.0]
      chs_with_sinusoids = [0, 1]
      for ix, freq in zip(chs_with_sinusoids, sinusoid_freqs):
          data[ix, :] += 2 * np.sin(np.pi * 2.0 * freq * times)
      return data, sfreq, sinusoid_freqs
  
file_path: mne-python/mne/time_frequency/tests/test_psd.py
imports: import numpy
  import pytest
  from numpy.testing import assert_allclose, assert_array_almost_equal, assert_array_equal
  from scipy.signal import welch
  from mne.time_frequency import psd_array_multitaper, psd_array_welch
  from mne.time_frequency.multitaper import _psd_from_mt
  from mne.time_frequency.psd import _median_biases
  from mne.utils import catch_logging
label_desc: Use image node_id 2 for calling a global function with example usage: _make_psd_data() and returns: data,  sfreq,  sinusoid_freqs